Even casual political-watchers know that Friday is the customary day for dropping bad news and dumping senior officials. No senior official is more deserving of being dumped than Environmental Protection Agency Administrator Scott Pruitt.

The Environmental Protection Agency’s inspector general plans to investigate whether Scott Pruitt, the agency’s embattled chief, acted improperly when he used an E.P.A. security detail for personal trips to the Rose Bowl, Disneyland and basketball games, among other places.

The latest probe brings the number of investigations into Mr. Pruitt’s use of taxpayer money and possible ethics violations to 10.

Ten? There are scandals concerning first-class travel, a $43,000 soundproof booth, an apartment leased from the wife of a lobbyist, outsize pay increases for top aides (one of whom allegedly spent time on Pruitt’s housing search, a violation of law if true), $10,200 to lease a super-duper upgraded SUV, retaliation against aides who objected to his spending sprees and “$45,000 in government money to fly five people to Australia to prepare for a planned trip that was later canceled” (according to a new Reuters report).

With the exception of the president himself, there is no Cabinet secretary or senior official who has so unabashedly wasted the taxpayers’ money on his own creature comforts.

Until now, right-wing activists and GOP lawmakers who are enraptured by his climate-change denial and attacks on Obama administration-era regulations have largely given Pruitt a pass. I suppose if you’ve blown a hole in the budget to the tune of $804 billion this year ($139 billion more than 2017) and $2.7 trillion (over 10 years) more than previously calculated, a few hundred thousand dollars is pocket change. Really, who among us would begrudge the EPA chief a security detail bigger than the attorney general’s, or more than $100,000 in European travel (even though, thanks to Pruitt, we’ve exited from the Paris climate accord)?

Previously, conservative Republicans had shown a reluctance to question the actions of top Trump administration officials. Their new outspokenness against a prominent architect of President Trump’s regulatory rollback represents a major break from the past.

In an interview this week, Senator John Boozman of Arkansas said of Mr. Pruitt, “I think there are legitimate concerns about him.” He applauded Mr. Pruitt’s industry-friendly environmental policies, but said, “I think the president at some point is going to weigh in.” Mr. Boozman serves on the Senate environment panel as well as the powerful Appropriations Committee, which controls the E.P.A.’s spending. . . .

Even Sen. John Barrasso (R-Wyo.), chairman of the Senate Environment and Public Works Committee, has gotten perturbed about the privacy booth. “It is critical that E.P.A. and all federal agencies comply with notification requirements to Congress before spending taxpayer dollars,” he said. “E.P.A. must give a full public accounting of this expenditure and explain why the agency thinks it was complying with the law.” And over in the House, Oversight and Government Committee Chairman Rep. Trey Gowdy (R-S.C.) bestirred himself to demand a slew of documents and transcribed interviews with key Pruitt associates.

Trump’s nonexistent ethical standards for himself and his family give his top advisers a green light to treat the Treasury as their own piggy bank. Pruitt’s mistake may have been in being so openly and comically piggish. Let’s hope he goes, if not today, on a Friday soon to come.

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